bcd_add.asm

介绍用Java解析网络数据的三种特殊方法

; This example shows how to add
; huge unpacked BCD numbers

#make_COM#

ORG     100h

; skip data:
JMP     start

; number of digits to
; process:
len     EQU     5

; first number is: '79,521':
num1    DB      1,2,5,9,7
; second number is: '82,191':
num2    DB      1,9,1,2,8

; for keeping result,
; result will be '161,712':
sum     DB      6 DUP (0)


start:  ; entry point.

; digit pointer:
XOR     BX, BX

; setup the loop:
MOV     CX, len 
        
next_digit:

        ; add digits:
        MOV     AL, num1[BX]
        ADC     AL, num2[BX]
        
        ; ASCII adjust:
        AAA
        
        ; store result:
        MOV     sum[BX], AL
        
        ; point to next digit:
        INC     BX
        
        LOOP    next_digit

; include carry in result (if any):
ADC     sum[BX], 0


; print out the result:
MOV     CX, len+1
; start printing from
; less significant digit:
MOV     BX, len

print_d:
        MOV     AL, sum[BX]
        ; convert to ASCII char:
        OR      AL, 30h

        MOV     AH, 0Eh
        INT     10h
        
        DEC     BX
        
        LOOP    print_d

RET

END